Torque reaction control link

ABSTRACT

A suspension system for a motor vehicle that controls torque reaction comprising a chassis a rigid drive axle, an opposite axle, a road wheel attached to each end of each axle, at least one torque reaction control link positioned longitudinally of the motor vehicle between the road wheels, at least two longitudinal control arms attached proximate the road wheels, for longitudinal control of the drive axle, so that the at least one torque reaction control link has a longitudinal plane that extends longitudinally of the motor vehicle and whereby the effective projection lines of the at least two longitudinal control arms and the longitudinal plane of the at least one torque reaction control link intersect each other in the direction of the opposite axle, forming a convergent angle and that when a force moves the rigid drive axle vertically up the convergent angle does not increase.

This application is a divisional from patent application Ser. No.10/909,189 and claims priority of U.S. Provisional Patent Application60/491,503, filed on Jul. 31, 2003, titled: Torque Reaction ControlLink.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to a rigid drive axle suspension system for motorvehicles.

2. Description of Prior Art

Typically, as part of an automobiles suspension, the driveshaft betweenthe engine/transmission and the rigid drive axle gear housing isenclosed in a “torque tube.” The torque tube is rigidly attached to adrive axle/gear housing assembly at one end and the other end has a“ball” that is enclosed by “ball drive housing” that is attached to theoutput end of the transmission. Inside the “ball” is the universal jointthat rotates the driveshaft inside the “torque tube.” At the axle gearhousing the driveshaft rotates the pinion gear through a straightsplined coupling.

This design has severe limitations in that the complete axle housing hasto pivot from the “ball” at the transmission in all planes. This makesit difficult to control the bump and roll steer of the axle as desired.

Presently, many race cars use a modified form that incorporates asliding or “slipper ball” end of the torque tube that allows the torquetube's length to change. This allows some design freedom, but still haslimitations, in that there is no allowance for lateral shifting of theaxle perpendicular to the torque tube. To overcome these shortcomingsmany other cars now use a torque arm with an open driveshaft. The torquearm is rigidly attached to the axle housing and extends toward thetransmission. The end of the torque arm attached to the chassis near thetransmission may be mounted in rubber. Sometimes it is attached to thechassis through a pivotally connected short vertical link.

Other designs typically have the torque arm attached to the chassisthrough a shock absorber with a parallel spring. This allows the end ofthe torque arm to move in all planes with the vertical plane controlledby the spring and shock absorber.

A torque arm has limitations on the length of the side view swing arm(SVSA) because of the placement of the engine/transmission in thechassis of the vehicle. It may also intrude into the body of thevehicle.

All of these designs are limited, because the length of the torque tubeor torque arm is restricted by the distance between the rigid drive axleand the transmission. Because of this limitation, the torque reaction isfed into the chassis at less than one half of the wheelbase of thevehicle. This causes the torque reaction to lift the chassis both at thefront and at the rear. The lifting of the chassis at the end where thedrive axle is located decreases the sprung weight and increases theundamped weight on the drive axle, thereby reducing the control of theaxle by the shock absorbers, when the wheels and axle move verticallyover irregular terrain.

There is also a considerable change of the pinion angle in the negativedirection when the axle is displaced vertically with the short torquetube or torque arm. This change in the negative direction of pinionangle causes forward rotational scrub of the tire contact patch on theground, and when accelerating, a loss of traction. Pinion angle, usuallymeasured in degrees is the convergent angle formed by the planes of thehorizon and the longitudinal axis of the pinion gear intersecting. Zeropinion angle is when the planes are parallel. Negative pinion angle iswhen the planes are convergent toward the center of the vehicle andpositive pinion angle is when they are convergent away from the center.

Various vehicle suspension systems have been designed to allow a vehicleto maintain traction of the drive axle tires when accelerating overirregular terrain. U.S. Pat. No. 2,300,844 (Olley) discloses a four linksuspension having upper links that are shorter than the lower links. Inthis invention the instant center produced by the projection lines ofthe upper and lower links intersecting will move closer to the driveaxle when the axle goes into a bump condition. The problem with thisdesign is the side view swing arm (SVSA) is relatively short and becomesshorter with the movement of the instant center toward the drive axlewhich causes an increase in the pinion angle change in the negativedirection and the conversion of sprung weight on the drive axle todirect vertical force or undamped weight on the tires or road wheelsthus decreasing the ability of the tires to maintain traction overirregular surfaces while accelerating.

Another vehicle suspension systems is disclosed in U.S. Pat. No.3,575,253 (Brumm) in which a rigid driven rear axle is connectedadjacent each end of the vehicle body by single longitudinal link and bya spring strut consisting of a helical spring and a telescopic shockabsorber. The projected line of the link intersects with the projectedline of the vehicles chassis and the resulting instant center lies at apoint beyond the axle opposite the drive axle. This awkwardconfiguration results in the instant center shifting from one end of thevehicle to the opposite end when the drive axle moves into a bumpcondition. The problem with this design is that the when the drive axlemoves into a bump condition the torque reaction of the axle whenaccelerating will pull the vehicle's chassis down at the drive axledecreasing available chassis clearance to the ground, drive axleclearance to the chassis and the springs and shock absorbers availablestroke. Another problem with this design is that it calls for the springstrut or shock absorber bearing the axle's reaction forces in a bendingmode.

Thus it is readily apparent that there is a longfelt need for a vehiclesuspension system that positions the instant center closer to theopposite axle that will remain at a relatively static position or moveaway from the rigid drive axle toward or beyond the opposite axle duringa bump condition. A significant deficiency with the previous developedsolutions, as well as many other similar devices, is that they provide avehicle suspension system that limits the ability of the vehicle's driveaxle tires to maintain traction when accelerating over irregular terrainand/or puts the drive axle reaction forces on the spring strut or shockabsorber rather than the axle attachment structures. The presentinvention satisfies the above-mentioned needs, as well as others, andovercomes the deficiencies in devices heretofore developed.

SUMMARY OF THE INVENTION

The invention relates to a suspension system for a motor vehicle thatcontrols the torque reaction of the rigid drive axle in combination withthe longitudinal control of the rigid drive axle comprising a chassis, arigid drive axle, an opposite axle and road wheels attached to the endsof each axle, a torque reaction control link positioned longitudinallyof the motor vehicle between the road wheels and with one or two pairsof longitudinal control arms pivotally attached to the axle attachmentstructures that are rotatably mounted on the rigid drive axle proximatethe road wheels, positioned longitudinally of the motor vehicle. Thetorque reaction control link is for controlling torque reaction of therigid drive axle in combination with the longitudinal control arms. Thetorque reaction control link is attached between the road wheels at therigid drive axle at a lower elevation than the rigid drive axleattachment point of the longitudinal control arms. Each pair oflongitudinal control arms are pivotally connected to the rigid driveaxle at one end and to the chassis at the other end, so that each of thelongitudinal control arms has an effective projection linelongitudinally of the motor vehicle. The torque reaction control link ispivotally connected to the rigid drive axle at one end and to thechassis at the other, so that the torque reaction control link has alongitudinal plane that extends longitudinally of the motor vehicle andwhereby the effective projection lines of the pair or pairs oflongitudinal control arms and the longitudinal plane of the torquereaction control link intersect each other toward the opposite axle andforming a convergent angle which results in a side view swing arm (SVSA)any length desired and that when a force moves the rigid drive axlevertically up the side view swing arm (SVSA) remains the same length orlengthens and the convergent angle does not increase.

It is an object of the present invention to provide a torque reactioncontrol link in a lower position than a torque tube or an open driveshaft with a torque arm so that there is no intrusion into the vehiclesbody.

It is a further object to provide a torque reaction control link on arigid drive axle suspension with a proper length and installation anglefrom horizontal and a side view swing arm (SVSA) that may be any lengthdesired that will remain the same or lengthen when the axle moves upvertically into a bump condition.

Still a further object of the present invention is to provide a torquereaction control link suspension that minimizes pinion angle change inthe negative direction when the axle moves up vertically into a bumpcondition.

Still another object of the present invention is to provide a torquereaction control link suspension to minimize the conversion of sprungweight on the drive axle to an undamped vertical force on the tires.

Still another object of the present invention is to provide a torquereaction control link suspension for a rigid drive axle suspension thatallows a vehicle to maintain traction of the drive axle tires whenaccelerating over irregular terrain.

Still another object of the present invention is to provide a torquereaction control link suspension in which no bending moments will beinduced into the shock absorbers or spring struts.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a prior art torque tube rigid drive axlesuspension for a motor vehicle.

FIG. 2 is a top view of a prior art torque tube rigid drive axlesuspension for a motor vehicle.

FIG. 3 is a side view of a prior art torque arm rigid drive axlesuspension for a motor vehicle.

FIG. 4 is a top view of a prior art torque arm rigid drive axlesuspension for a motor vehicle.

FIG. 5 is a side view of a partially decoupled open or closed tube rigiddrive axle suspension for a motor vehicle depicting a preferredembodiment of a torque reaction control link of the present invention.

FIG. 6 is a top view of a partially decoupled open or closed tube rigiddrive axle suspension for a motor vehicle depicting a preferredembodiment of a torque reaction control link of the present invention.

FIG. 7 is a side view of a partially decoupled open or closed tube rigiddrive axle inverted three link suspension system for a motor vehicledepicting another preferred embodiment of a torque reaction control linkof the present invention.

FIG. 8 is a top view of a partially decoupled open or closed tube rigiddrive axle inverted three link suspension systems for a motor vehicledepicting another preferred embodiment of a torque reaction control linkof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

This application is a divisional from patent application Ser. No.10/909,189 and claims priority of U.S. Provisional Patent Application60/491,503, filed on Jul. 31, 2003, titled: Torque Reaction ControlLink.

At the outset, it should be clearly understood that like referencenumerals are intended to identify the same structural elements,portions, or surfaces consistently throughout the several drawingfigures, as may be further described or explained by the entire writtenspecification of which this detailed description is an integral part.These embodiments should not be construed as the only applications thatthe inventions may be used.

A significant deficiency with the previously developed suspensionsystems such as those depicted in FIGS. 1-4, as well as many othersimilar devices, is that they provide a vehicle suspension system thatlimits the ability of the vehicle drive axle tires to maintain tractionwhen accelerating over irregular terrain and/or puts the drive axlereaction forces on the spring strut or shock absorbers rather than theaxle attachment structures. These axles are fitted with rotatable axleattachment structures called birdcages. When birdcages are used the axlebecomes known as decoupled. A decoupled rigid drive axle is one in whichthe longitudinal control and the torque reaction control are independentof each other. A birdcage is a device with a bearing that has an insidediameter that fits over the outside diameter of an open or closed axletube. The bearing is retained in a housing and the housing has upper andlower brackets rigidly attached to it. The brackets are nominallypositioned above and below the axle's vertical center. Each bracket hasan attachment point for pivotally connecting a longitudinal control arm.An open tube axle is a rigid drive axle that serves two purposes: theopen tube axle is a rigid beam that connects the wheels together and itrotates the wheels simultaneously. Birdcages are needed to allow theopen tube axle to rotate. Sometimes, closed tube rigid drive axles arefitted with birdcages because the design of the suspension systemrequires a decoupled axle but for various reasons an open tube axle isnot wanted. A closed tube rigid drive axle has the rotating axlesenclosed in housings called tubes. The tubes extend outward from bothsides of the drive axle's gear housing to hubs and wheels. Any rigiddrive axle that uses bird cages must have a device such as a torque tubeor a torque arm that is rigidly attached to the drive axle's gearhousing and pivotally attached to the vehicle's chassis to keep the gearhousing from rotating about the axle. The torque reaction control linkof the present invention replaces the heavier and more costly torquetube or torque arm and when used with the birdcages the rigid drive axlebecomes partially decoupled.

The invention relates a torque reaction control link for a partiallydecoupled open or a closed tube rigid drive axle suspension for a motorvehicle using two pairs of longitudinal control arms (lower longitudinalcontrol arm 24 and upper longitudinal control arm 22 constitutes apair). Each longitudinal control arm has two pivotal attachment points,one at the axle and one at the chassis. Each longitudinal control armmay be arranged to extend longitudinally in the same direction or inopposite direction from the rigid drive axle to the chassis. Thelongitudinal control arms may be of equal or unequal length, parallel ornot parallel to each other. The upper and lower longitudinal controlarms will have an effective projected longitudinal line (projection line23). The preferred embodiment of the present invention uses a straightline mechanism commonly called a Watt's Link, proximate each road wheel,for the sole longitudinal control of the rigid drive axle. Thismechanism is designed using three components. In this application agenerally or near vertical center component provides a means topivotally connect two generally or near horizontal components to therigid drive axle. The generally or near vertical component is an axleattachment structure called a birdcage which is rotatably mounted andlaterally secured as a means for attachment to the rigid drive axle. Thetwo approximately horizontal components are called upper and lowerlongitudinal control arms. The upper longitudinal control arm ispivotally connected to the upper bracket of the birdcage and the lowerlongitudinal control arm is pivotally connected to the lower bracket ofthe birdcage. The opposite ends of each of the longitudinal control armsare pivotally connected to the chassis of the motor vehicle, in oppositedirections longitudinally and approximately perpendicular from the rigiddrive axle. With proper design and arrangement of the components therigid drive axle can be made to move in an approximate straight verticalline over a short span. Perpendicular to the approximate straightvertical movement of the rigid drive axle is the effective longitudinalcontrol arm of the axle. Because the vertical movement is nearlystraight the longitudinal control point is close to infinity; thus aneffective projected longitudinal control arm is near infinite in length.The torque reaction control link of the present invention is limited inlength and is positioned longitudinally in the motor vehicle, lower thanthe longitudinal control arms at the rigid drive axle attachment pointand the installed horizontal slope of the torque reaction control linkmust be such that the longitudinal plane through the pivotal connectionpoints at the rigid drive axle and the motor vehicle's chassis of thetorque reaction control link must converge and intersect with theeffective projected longitudinal control arm of the Watt's Link, towardthe opposite axle. The point where they intersect is called an instantcenter and the horizontal distance from the rigid drive axle to theinstant center is called a side view swing arm. When the rigid driveaxle moves vertically up, the horizontal slope of the torque reactioncontrol link will change more than the slope of the effective projectionof the longitudinal control arm of the Watt's Link, because the torquereaction control links' length is shorter than the effective length ofthe longitudinal control arm. The convergent angle formed by theintersection of the longitudinal plane of the torque reaction controllink and the effective projected longitudinal control arm of the Watt'sLink will become more acute and the instant center will move furtherfrom the rigid drive axle toward the opposite axle or beyond. The sideview swing arm will lengthen.

Another preferred embodiment of the invention (as shown in FIG. 7)relates to a torque reaction control link for a partially decoupled openor a closed tube rigid drive axle suspension using a pair of triangularlongitudinal control arms 25 each generally configured to be attached tothe vehicle at three connection points: two near vertical pivotalattachment points at the rigid drive axle and a pivotal attachment pointat the chassis.

Adverting now to the drawings, FIG. 1 is a side view of a prior arttorque tube rigid drive axle suspension for a motor vehicle. Torque tube12 is rigidly attached to rigid drive axle/gear housing assembly 10 atone end, the other end is attached to ball 13 that is enclosed in ahousing (not shown) affixed to the transmission output end. The sideview swing arm (SVSA) 14 for a torque tube suspension is the horizontaldistance from the center of rigid drive axle/gear housing assembly 10 topivot point 15 of the torque tube 12 at the output end of the vehicletransmission. A problem with this basic design is that the torque tubehas limitations on the length of the side view swing arm (SVSA) becauseof the placement of the engine/transmission in the chassis of thevehicle. Furthermore when the axle moves vertically into bump the pinionangle changes in a negative direction which results in forwardrotational scrub of the road wheels. There has been a longfelt need tolengthen the side view swing arm without moving the engine/transmissionfurther from the rigid drive axle.

FIG. 2 is a top view of prior art torque tube rigid drive axlesuspension for a motor vehicle. Torque tube 12 is rigidly attached torigid axle/gear housing assembly 10 which is mounted to rigid drive axle11. Mounted at opposite ends of rigid drive axle 11 are road wheels 16.Rigid drive axle 11 in this type of suspension system is either an opentube or a closed tube drive axle. An open tube is a rigid drive axlethat serves two purposes: it is a rigid beam that connects the left andright road wheels together and it rotates the road wheelssimultaneously. A closed tube axle is a rigid drive axle that has therotating axles enclosed in housings called tubes that extend from bothsides of the gear housing outward to the road wheels. FIGS. 1 and 2 donot show transmission, chassis, axle attachment structures, longitudinalcontrol arms, track bar, springs or shock absorbers for clarity.

FIG. 3 is a side view of prior art torque arm rigid drive axlesuspension for a motor vehicle. Torque arm 18 is oriented in alongitudinal direction toward the transmission. One end of torque arm 18is rigidly attached to a rigid drive axle/gear housing assembly 10 andthe other end is attached to the chassis near the transmission and maybe mounted in rubber or pivotally connected to chassis 30 throughvertical link 19. SVSA 14 for a torque arm used in conjunction with arigid drive axle suspension is the horizontal distance from the centerof rigid drive axle/gear housing assembly 10 to pivot point 17 proximatethe vehicles chassis. The same problem that exists with a suspensionsystem that includes a torque tube is present with this basic design.The SVSA for the torque arm is dependent on the length of the torque armwhich in turn is limited by the placement of the engine/transmission inthe chassis of the vehicle. Clearly there has been a longfelt need havea longer SVSA without having to move the engine/transmission furtherfrom the drive axle. The vehicle suspension system of the presentinvention positions the instant center closer to the opposite axle, andit will remain at a relatively static position or move away from thedrive axle toward or beyond the opposite axle during a bump conditionand thus does not have the limitation in length of the side view swingarm.

FIG. 4 is a top view of a prior art torque arm rigid drive axlesuspension for a motor vehicle. Mounted at opposite ends of rigid driveaxle 11 are road wheels 16. Torque arm 18 is rigidly attached to rigiddrive axle/gear housing assembly 10. FIGS. 3 and 4 do not showtransmission, drive shaft, axle attachment structures, longitudinalcontrol arms, track bar, springs or shock absorbers. The drawings of thedrive axles shown in FIGS. 1-4 do not show any longitudinal control forclarity.

Unlike the decoupled rigid drive axle depicted in FIGS. 1-4 thepreferred embodiments of the instant invention depicted in FIGS. 5-8show a torque reaction control link for a partially decoupled open or aclosed tube rigid drive axle suspension. A partially decoupled rigiddrive axle uses the torque reaction control link of the presentinvention and the longitudinal control arms in combination, to controlthe axle's torque reaction, but the longitudinal control of the axle isindependent or decoupled from the torque reaction control.

FIG. 5 is a side view of a partially decoupled open or closed tube rigiddrive axle suspension for a motor vehicle depicting torque reactioncontrol link 28 of the present invention. At the outboard ends of rigiddrive axle 11, near the road wheels 16, axle attachment structures 20are rotatably mounted and laterally secured on to rigid drive axle 11.Upper longitudinal control arms 22 are pivotally connected to the upperbrackets on axle attachment structures 20 and their opposing ends arepivotally connected to chassis 30 in the direction away from theopposite axle 31. Upper longitudinal control arms are positioned abovethe rigid drive axle and extend longitudinally of the vehicle. Lowerlongitudinal control arms 24 are positioned longitudinally of thevehicle and are pivotally connected to lower brackets on rotatable axleattachment structures 20 and their opposite ends are pivotally connectedto chassis 30 in the direction of the opposite axle 31. Lowerlongitudinal control arms 24 are pivotally connected to axle attachmentstructures 20 at an elevation below the rigid drive axle. The two pairsof longitudinal arms control the fore and aft location of the axle inrelationship to the vehicle, independent of the torque reaction controland therefore the longitudinal control is decoupled. Lower axleattachment structure 26 is rigidly attached to the underside of therigid drive axle/gear housing 10 to which one end of torque reactioncontrol link 28 is pivotally connected. The other end of torque reactioncontrol link 28 is pivotally connected to chassis 30 toward the oppositeaxle 31. Torque reaction control link 28 is attached at an attachmentpoint on rigid drive axle at a lower elevation than the attachmentpoints of longitudinal control arms 22 and 24 at the rigid drive axle.The torque reaction control of the axle is achieved with thelongitudinal control arms working in combination with the torquereaction control link, therefore the torque reaction control is notdecoupled. There is an effective projection line 23 for longitudinalcontrol for rigid drive axle 11, used in conjunction with birdcages asthe axle attachment structures. If upper and lower longitudinal controlarms 22 and 24 are not parallel to each other longitudinally, theeffective projection line 23 for longitudinal control passes through theconvergent point of upper and lower longitudinal control arms 22 and 24individual projected lines 21, and the longitudinal/vertical center ofthe rigid drive axle. If upper and lower longitudinal control arms 22and 24 are parallel to each other longitudinally as shown in FIG. 5;effective projection line 23 for longitudinal control is parallel toupper and lower longitudinal control arms 22 and 24, and passes throughthe longitudinal/vertical center of rigid drive axle 11.

Effective projection line 23 for longitudinal control converges at anangle with longitudinal plane 27 for the torque reaction control linkand the point at which effective projection line 23 and longitudinalplane 27 intersect is instant center 29. Instant center 29 is the pointfrom where the complete rigid drive axle/gear housing assembly 10rotates about when rigid drive axle 11 moves vertically. The horizontaldistance from the center of the rigid drive axle/gear-housing assemblyto instant center 29 is SVSA 14 for this embodiment of the presentinvention. The change of the horizontal slope of effective projectionline 23 for longitudinal control will be less than the change of theslope for torque reaction control link 28 when the rigid drive axle 11moves up vertically. The result of the upward movement of rigid driveaxle 11 is that instant center 29 will move away from rigid drive axle11 and SVSA 14 will lengthen. In both embodiments of the presentinvention torque reaction control link 28 may be a single link, a pairof parallel links, a pair of links convergent toward the chassis fromthe axle, a pair of links convergent toward the axle from the chassis, atriangular A-Arm with the apex at the chassis and the pair of oppositeends at the axle or the apex at the axle and the pair of opposite endsat the chassis. Torque reaction control link 28 may have a hydraulictracking damper with a compression spring, a spring rod with compressionsprings, or a torque absorber using resilient strut bushings or springs,all operatively arranged as part of its length.

FIG. 6 is a top view of a partially decoupled open or closed tube rigiddrive axle suspension for a motor vehicle depicting torque reactioncontrol link 28 of the present invention, longitudinally positioned inbetween road wheels 16 with one end pivotally connected to the chassis30 toward the opposite axle 31. The opposite end is pivotally connectedto lower axle attachment structure 26 (not visible on drawing) becauseit is rigidly attached below to the rigid drive axle/gear housingassembly 10. Axle attachment structures 20 are rotatably mounted andlaterally secured on to the outboard ends of rigid drive axle 11, nearroad wheels 16. One end of the upper longitudinal control arms 22 areeach pivotally connected to the upper brackets on axle attachmentstructures 20, and their opposite ends are pivotally connected tochassis 30 away from the opposite axle 31. One end of the lowerlongitudinal control arms 24 are each pivotally connected to the lowerbrackets on the axle attachment structures 20 and their opposite endsare pivotally connected to chassis 30 disposed longitudinally in thedirection of the opposite axle 31.

FIG. 7 is a side view of a partially decoupled open or closed tube rigiddrive axle inverted three link suspension for a motor vehicle depictingtorque reaction control link 28 as the third link of the presentinvention. Another preferred embodiment of the invention relates to atorque reaction control link for a partially decoupled open or a closedtube rigid drive axle suspension using a pair of triangular longitudinalcontrol arms 25 each generally configured to be attached to the vehicleat three connection points: two near vertical pivotal attachment pointsat the rigid drive axle and a pivotal attachment point at the chassis.Near road wheels 16, axle attachment structures 20 are mounted andlaterally secured on to rigid drive axle 11. Triangular longitudinalcontrol arms 25 each have one end pivotally connected to an axleattachment structure 20, and their opposite ends are pivotally connectedto chassis 30 toward the opposite axle 31. Lower axle attachmentstructure 26 is rigidly attached to the underside of rigid drive axle11, between road wheels 16. One end of torque reaction control link 28is pivotally connected to the lower axle attachment structure 26 and itsopposite end is pivotally connected to chassis 30, toward the oppositeaxle 31. Torque reaction control link 28 has to be positioned lower thanthe longitudinal control arms at the rigid drive axle. Effectiveprojection line 23 for longitudinal control converges at an angle witheffective longitudinal plane 27 for the torque reaction control link,and where the lines intersect is instant center 29. Instant center 29 isthe point from where the complete rigid drive axle/gear housing assembly10 rotates about when rigid drive axle 11 moves vertically. Thehorizontal distance from the center of the rigid drive axle/gear-housingassembly to instant center 29 is SVSA 14 for this embodiment of thepresent invention. The change of the horizontal slope of effectiveprojection line 23 for longitudinal control will be less than the changeof the slope for torque reaction control link 28 when the rigid driveaxle 11 moves up vertically. The result of the upward movement of rigiddrive axle 11 is that instant center 29 will move away from rigid driveaxle 11 and SVSA 14 will lengthen.

FIG. 8 is a top view of a partially decoupled open or closed tube rigiddrive axle inverted three link suspension for motor vehicle depictingtorque reaction control link 28 as the third link of the presentinvention. Torque reaction control link 28 is longitudinally positionedbetween the road wheels 16 and one end is pivotally connected to chassis30 toward opposite axle 31. The opposite end of torque reaction controllink 28 is pivotally connected to lower axle attachment structure 26,because it is rigidly attached below to rigid drive axle/gear housingassembly 10. Near road wheels 16, axle attachment structures 20 aremounted and laterally secured on to rigid drive axle 11. Triangularlongitudinal control arms 25 each have one end pivotally connected tothe upper and lower axle rotatable attachment structure 20 with theiropposite ends pivotally connected to chassis 30, toward the oppositeaxle 31. No track bar, springs or shock absorbers are shown in FIGS. 5-8for clarity.

A vehicle configured with a suspension system of the instant inventionwill be able to maintain traction of the drive axle tires, whenaccelerating over irregular terrain because there is less pinion anglechange in the negative direction. The change is caused by the radius ofthe SVSA moving in an arc when the axle is vertically displaced. Thischange can be almost instantaneous when the axle and tires go into abump condition. If the vehicle is accelerating at or near the limit ofadhesion and the axle and tires are suddenly rotated in a forwarddirection by the pinion angle change, the tires are forced to scrub onthe road surface a distance proportional to the angular change at theradius of the tires. This causes the tires to lose adhesion or traction.

The drive axle tires of a vehicle equipped with torque reaction controllink 28 of the present invention will maintain traction whenaccelerating over irregular terrain because there is less sprung weightremoved from the drive axle and converted to an undamped vertical forceon the tires. This conversion is caused by the torque reaction acting onthe chassis in an upward vertical direction, through the suspensionlinks at the instant center of SVSA 14. With a SVSA as long as thewheelbase there is no sprung weight removed from the drive axle, andmore favorable sprung to unsprung weight ratio is maintained. Thisenables the shock absorbers to control the sprung and unsprung masses.The tires will then continue to provide traction.

While the invention has been described with reference to certainpreferred embodiments, it will be appreciated by those skilled in theart that modifications and variations may be made without departing fromthe spirit and scope of the invention.

REFERENCE NUMERALS IN DRAWINGS

-   10. Axle/Gear Housing Assembly-   11. Rigid Drive Axle-   12. Torque Tube-   13. Ball-   14. SVSA-   15. Pivot Point-   16. Road Wheels-   17. Pivot Point-   18. Torque Arm-   19. Vertical Link-   20. Axle Attachment Structure-   21. Projected Lines-   22. Upper Longitudinal Control Arm-   23. Projection Line-   24. Lower Longitudinal Control Arm-   25. Triangular Longitudinal Control Arm-   26. Lower Axle Attachment Structure-   27. Longitudinal Plane-   28. Torque Reaction Control link-   29. Instant Center-   30. Chassis-   31. Opposite Axle

1) A suspension system for a motor vehicle that controls torque reactioncomprising: a chassis; a rigid drive axle; an opposite axle; a roadwheel attached to each end of each axle; at least one torque reactioncontrol link positioned longitudinally of said motor vehicle betweensaid road wheels; at least two longitudinal control arms attached atsaid rigid drive axle proximate said road wheels, for longitudinalcontrol of said rigid drive axle, attached at said rigid drive axlebetween said road wheels at a higher elevation than the rigid drive axleattachment point of said at least one torque reaction control link, forcontrolling torque reaction of said rigid drive axle in combination withsaid at least one torque reaction control link; a means for pivotallyconnecting one end of each of said at least two longitudinal controlarms to said rigid drive axle proximate said road wheels and the otherend of each said longitudinal control arms to said chassis, so that eachof said longitudinal control arms has an effective protection linelongitudinal of said motor vehicle; a means for pivotally connecting oneend of said at least one torque reaction control link to said rigiddrive axle and other end to said chassis, so that said at least onetorque reaction control link has a longitudinal plane that extendslongitudinally of said motor vehicle and whereby said effectiveprojection lines of said at least two longitudinal control arms and saidlongitudinal plane of said at least one torque reaction control linkintersect each other in the direction of said opposite axle, forming aconvergent angle and that when a force moves said rigid drive axlevertically up said convergent angle does not increase. 2.) Thesuspension system according to claim 1 wherein said means for pivotallyconnecting one end of said at least one torque reaction control link tosaid rigid drive axle is a lower axle attachment structure. 3.) Thesuspension system according to claim 1 wherein said means for pivotallyconnecting one end of each of said at least two longitudinal controlarms to said rigid drive axle are rotatable axle attachment structuresmounted on said rigid drive axle, proximate each of said road wheels,each of said rotatable axle attachment structure having two nearvertical pivotal attachment points for said at least two longitudinalcontrol arms. 4.) The suspension system according to claim 1 whereinsaid a length of said torque reaction control link is shorter than theeffective length of each of said at least two longitudinal control arms.5.) A suspension system for a motor vehicle that controls torquereaction comprising: a chassis; a rigid drive axle; an opposite axle; aroad wheel attached to each end of each axle; two upper longitudinalcontrol arms and two lower longitudinal control arms for longitudinalcontrol of said rigid drive axle, attached at said rigid drive axleproximate said road wheels such that each said upper and lowerlongitudinal control arm has a length disposed longitudinally of saidvehicle and each said length of said upper longitudinal control arm isequal to each said length of said lower longitudinal control arm; atleast one torque reaction control link for torque reaction control ofsaid rigid drive axle positioned longitudinally of said motor vehicle;one end of said torque reaction control link is attached at said rigiddrive axle between said road wheels at a lower elevation than the rigiddrive axle attachment points of said two upper longitudinal control armsand said two lower longitudinal control arms and the other end of saidtorque reaction control link is attached to said chassis; a means forpivotally connecting one end of each of said upper longitudinal controlarms and one and end of each of said lower longitudinal control arms tosaid rigid drive axle proximate said road wheels and the other end ofsaid longitudinal control arms to said chassis, so that each of saidupper and lower longitudinal control arms has an effective projectionline longitudinal of said motor vehicle; a means for pivotallyconnecting one end of said at least one torque reaction control link tosaid rigid drive axle and other end to said chassis, so that said atleast one torque reaction control link has a longitudinal plane thatextends longitudinally of said motor vehicle and whereby said effectiveprojection lines of said at least two longitudinal control arms and saidlongitudinal plane of said at least one torque reaction control linkintersect each other in the direction of said opposite axle, forming aconvergent angle and that when a force moves said rigid drive axlevertically up said convergent angle does not increase. 6.) Thesuspension system according to claim 5 wherein said length of said upperlongitudinal control arms is shorter than the length of said lowerlongitudinal control arms. 7.) The suspension system according to claim5 wherein said length of said upper longitudinal control arms is longerthan the length of said lower longitudinal control arms. 8.) Thesuspension system according to claim 5 wherein said length of said upperlongitudinal control arms are disposed in parallel to said length ofsaid lower longitudinal control arms. 9.) The suspension systemaccording to claim 5 wherein said length of said upper longitudinalcontrol arms is not disposed in parallel to said length of said lowerlongitudinal control arms. 10.) The suspension system are according toclaim 5 wherein said length of said upper longitudinal control armsdisposed in an opposite direction from said rigid drive axle than saidlower longitudinal control arms. 11.) A suspension system for a motorvehicle that controls torque reaction comprising: a chassis; a rigiddrive axle; an opposite axle; a road wheel attached to each end of eachaxle; at least one torque reaction control link positionedlongitudinally of said motor vehicle between said road wheels attachedat one end at an attachment point on said rigid drive axle and attachedat the other end to said chassis; two triangular longitudinal controlarms each attached at an attachment point on said rigid drive axleproximate said road wheels at a higher elevation than the attachmentpoint of said at least one torque reaction control link on said rigiddrive axle, for longitudinal control of said rigid drive axle and forcontrolling torque reaction of said rigid drive axle in combination withsaid at least one torque reaction control link; a means for pivotallyconnecting said triangular longitudinal control arms to said rigid driveaxle proximate said road wheels and the other end of each of saidtriangular longitudinal control arm to said chassis disposed in thedirection of said opposite axle, so that each said triangularlongitudinal control arm has and effective projection line longitudinalof said motor vehicle; a means for pivotally connecting one end of saidat least one torque reaction control link to said rigid drive axle andother end to said chassis, so that said at least one torque reactioncontrol link has a longitudinal plane that extends longitudinally ofsaid motor vehicle and whereby said effective projection lines of saidtwo triangular longitudinal control arms and said longitudinal plane ofsaid at least one torque reaction control link intersect each other inthe direction of said opposite axle, forming a convergent angle and thatwhen a force moves said rigid drive axle vertically up said convergentangle does not increase. 12.) The suspension system according to claim11 wherein said length of triangular longitudinal control arm isdisposed in a direction away from of said opposite axle.